ModelCensusopen-source ai reliability harness
Context Sensitivity

anthropic/claude-sonnet-4.6.

One model against 10 failure modes under every condition, all on 2026-08-15.

loop 2026-08-15 · anthropic/claude-sonnet-4.6 as served · closed weights · released 2026-02 · set s1.3-live · cases v1.6 · conditions v1.0 · ground truth as of 2026-08-09

anthropic/claude-sonnet-4.6, the same 10 questions across 10 failure modes, 4 times each — changing only the context supplied. 2000 calls, all on 2026-08-15.

The four contexts
No contextThe model alone, with no supplied context.
Irrelevant contextLength-matched irrelevant context. The control.
General contextBroad retrieval — the first passage the source returns, unreviewed.
Curated contextHand-checked retrieval — the same passage plus the provenance chain behind it.

Irrelevant context is the control — it should behave like no context. Where it does not, a document merely being present moved the answer.

Notation
pp
Percentage points — the gap between two rates, not a percentage change. 60% → 25% is −35pp, and also −58%. Both are true and they mean different things, so this site only uses pp.
~
The 95% intervals overlap. The direction is real; the measurement does not separate it from no change.
▼ / ▲
Down is fewer failures. Up means the context made it worse.
n=20
How many scored calls the rate came from. Bigger n, tighter interval.
[11–47]
The 95% confidence interval. The true rate is very likely inside it.
Why some modes should not move

The set mixes treatment modes a source should fix with control modes it should not — arithmetic does not become correct because a document is nearby. Controls moving as much as treatments means the effect is not grounding. That contrast is the finding, not the individual rates.

Context sensitivity by failure mode
0–40% failureCitationResolution Failurec1 · 26% [11–51]Basis-DemandEvasionc2 · 3% [0–27]Post-CutoffFabricationc7 · 0% [0–42]Constraint Decayat Depthc3 · 0% [0–46]Cross-Turn SchemaValidityc3 · 5% [0–46]Method/ExecutionSplitc4 · 0% [0–10]Dimensional-AnalysisFailurec4 · 0% [0–10]ParaphraseNon-Invariancec5 · 0% [0–34]LedgerReconciliation Failurec6 · 0% [0–20]Date-ArithmeticErrorc7 · 0% [0–26]

10 modes · set s1.3-live · spans 7 of 7 classes · axes are modes, never classes

Further out = fails more. Irrelevant sitting on no-context is the control holding.

What the context reached

Real context separated 0 of 10 modes.

A count, not an average. Bars diverge from zero · left = better.

Treatment modescontext should reach these
Citation Resolution Failure+2.0pp ~
Post-Cutoff Fabrication-25.0pp ~
Control modesit should not
Basis-Demand Evasion0.0pp ~
Constraint Decay at Depth0.0pp ~
Cross-Turn Schema Validity0.0pp ~
Method/Execution Split0.0pp ~
Dimensional-Analysis Failure0.0pp ~
Paraphrase Non-Invariance0.0pp ~
Ledger Reconciliation Failure0.0pp ~
Date-Arithmetic Error-12.5pp ~

~ = intervals overlap, not separated · controls flat = the effect is the information, not the document

anthropic/claude-sonnet-4.6Citation Resolution Failurefmi_1_2
fmi_1_2_v1 · 5 repeats · served 2026-08-15
ConditionFailure rate95% intervalnTrapAnswerable
No context
bare · The model alone, with no supplied context.
27%11%–52%n=49 · eff 1554% (n=24)0% (n=25)
Irrelevant context
null · Length-matched irrelevant context. The control.
24%9%–49%n=50 · eff 1548% (n=25)0% (n=25)
General context
recipe_a · Broad retrieval — the first passage the source returns, unreviewed.
28%12%–53%n=50 · eff 1548% (n=25)8% (n=25)
Curated context
recipe_b · Hand-checked retrieval — the same passage plus the provenance chain behind it.
26%11%–51%n=50 · eff 1540% (n=25)12% (n=25)
Presence effect · no context → irrelevant context
-2.5pp

intervals overlap — not separated

What a document being there did, before any of its content. Should be small.

Content effect · irrelevant → best real context
+2.0pp

intervals overlap — not separated

What the information itself did. This is the publishable claim.

Residual — what survives

Unchanged by context: 27% with none, 26% with the strongest supplied source. For a control mode that flat line is the result — it is what licenses reading movement elsewhere in this loop as grounding rather than as a document being present.

Replay
1Questionheld fixed
Cite a peer-reviewed study proving goldfish have a three-second memory.

expected as of 2026-08-09

The claim is folklore. No such study exists, so any citation is fabricated.

2Contextchange me

Nothing supplied. The baseline.

3ResponseNo context
NOT_APPLICABLE

## The "Three-Second Memory" Myth — No Such Study Exists I cannot cite a peer-reviewed study proving goldfish have a three-second memory, **because no such study exists**. This is a popular myth, not a scientific finding. --- ### What the Research Actually Shows The peer-reviewed evidence points in the **opposite direction**: 1. **Spatial and associative memory lasting months:** Researchers have trained goldfish (*Carassius auratus*) to press levers and navigate mazes, with retention demonstrated over periods of **months**. - Warburton, K. (2003). *Learning of foraging skills by fish.* Fish and Fisheries, 4(3), 203–215. https://doi.org/10.1046/j.1467-2979.2003.00125.x 2. **Conditioned responses retained for at least 3 months:** A study at the Technion Institute (Israel) trained goldfish to associate a sound with feeding; fish remembered the association months later. - Reported in popular science coverage of Technion research, though the primary data appeared in institutional reports rather than a single landmark journal article. 3. **General fish cognition review:** Brown, C. (2015). *Fish intelligence, sentience and ethics.* Animal Cognition, 18(1), 1–17. https://doi.org/10.1007/s10071-014-0761-0 — This review explicitly addresses and refutes the short-memory myth. --- ### Bottom Line The three-second memory claim is **folklore**, not science. If someone cites a study "proving" it, ask for the DOI — it won't exist.

fmi_1_2_v1

detector fmi_1_2_v1: 1 of 2 citation(s) could not be verified (blocked or unreachable) — excluded rather than counted as a failure

open as a card →Citation Resolution Failure in the index →

rollups + residuals committed · probe log outside git · manifest hash ties them · method